Question

The phenotype of vestigial (short) wings (vg) in Drosophila melanogaster is caused by a recessive mutant gene that independently assorts with a recessive gene for hairy (h) body. Assume that a cross is made between a fly with normal wings and a hairy body and a fly with vestigial wings and normal body hair. The wild-type F1 flies were crossed among each other to produce 1024 offspring. Which phenotypes would you expect among the 1024 offspring, and how many of each phenotype would you expect?

Answer 1

Answer:

It is expected to obtain 576 individuals with normal wings and body with normal hair, 192 with normal wings and hairy body, 192 with vestigial wings and body with normal hair, and 64 with vestigial wings and hairy body.

Explanation:

Since only the wild-type of the offspring cross each other and since the parents have antagonistic phenotypic characters for each gene, all the progeny produced in the F1 is heterozygous with VgvgHh genotype, where

Vg: Normal wings.

eg: Vestigial wings.

H: Body with normal hair.

h: Hairy body.

Once F1 reproduces with each other, the Mendelian proportions 9/16, 3/16, 3/16, 1/16 expected in the F2 generation are produced.

Since in total there were 1024 individuals in the offspring, this amount is multiplied by the expected proportions, giving rise to the mentioned result.